Electromagnetic transducer having a low reluctance return path
AssigneeSTEP Technologies, Inc.
InventorEnrique Stiles
Life of this patent
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Abstract
An electromagnetic transducer, such as an audio speaker, includes a return path member which is a pole piece for external magnet geometries or a cup for internal magnet geometries. The magnetic flux return path for the primary drive magnet is through a first portion of the return path member. A first section of a low reluctance magnetic flux return path for a secondary drive magnet is through a second portion of the return path member. A magnetically conductive plate provides a second section of the low reluctance return path from the second portion of the return path member to the secondary drive magnet.
Claims1
An electromagnetic transducer comprising:
- a cup including a back plate portion and a substantially cylindrical wall portion;
- a first magnet magnetically coupled to the back plate portion of cup;
- a drive plate magnetically coupled to the first magnet opposite the back plate portion of the cup, the drive plate defining a drive magnetic air gap with the wall portion of the cup;
- a second magnet magnetically coupled to the drive plate opposite the first magnet, and having a magnetic polarity substantially opposite a magnetic polarity of the first magnet;
- a return path plate magnetically coupled to the second magnet opposite the drive plate, and defining a low reluctance return path gap with the wall portion of the cup;
- wherein magnetic flux flows over the return path gap in an orientation substantially opposite that of flux flowing over the drive magnetic air gap.
Dependencies are inferred from the claim text.